【摘要】 为明确对氨基苯横酸钠对不同植物体内叶酸合成选择性抑制的作用机制,有必要检测该化合物进入植物体内后是否形成了结合态对氨基苯磺酸钠,但是目前尚无直接测定结合态对氨基苯磺酸钠的方法。本研究在李禄先等测定小麦体内对氨基苯磺酸总含量的方法(Ⅰ法)基础上提出了测定植物体内游离对氨基苯磺钠含量的方法(Ⅲ法),并对Ⅰ法作了三点改进:①用0.2M磷酸钠缓冲液(pH7.2)代替蒸馏水提取植物细胞内含物;②用30％三氯乙酸代替盐酸水解样品;③不用氢氧化钠。从而克服了采用Ⅰ法时由于长豇豆体内干扰因子的影响而使测定值显著偏低的缺点。这种改进方法对结合态对氨基苯磺酸(对乙酰氨基苯磺酸)有很强的水解能力,可将对氨基苯磺酸从其结合状态中完全释放出来,而且,对于只含有游离态对氨基苯磺酸钠的植物样品,改进方法和测定游离态药物的Ⅲ法的测定结果无差异(P=0.1)。这表明改进方法是一个测定植物体内对氨基苯磺酸钠总含量的理想方法,可以和测定游离态药物的Ⅲ法配合用以检测植物体内的结合态对氨基苯磺酸钠。更多还原

【Abstract】 In order to elucidate the inhibitory effect of sodium sulfanilate on the biosynthesis of follc acid in different plants, it is necessary to demonstrate if there is formation of sodium sulfanilate-conjugated compound. Due to the unavailablity of a method for testing the conjugate of sodium sulfanilate, a modified one of Li’s method (method I) , which is traditionally used to determine the total content of sulfanillic acid in wheat, was developed for analyzing the total content of the test compound,including bound and free ones. The modifications were (1) 0.2 M sodium phosphate buffer solution (pH 7.2) was used for the extraction of plant tissue instead of distilled water, (2) thirty percent trichloroacetic acid was used for hydrolysis of bound sodium sulfanilate instead of HC1; and (3) no NaOH was used. Free sodium sulfanilate in plant tissue was quantitatively analyzed by Li’s method with a deletion of the procedures of HC1 hydrolysis and NaOH neutralization. Such method was termed method Ⅱ.The original Li’s method was found not suitable for analyzing sodium sulfanilate in asparaqus long bean plant, showing an under-reco very of the test compound added to the sap of the plant. But the modified msthod was shown to be excellent in ovarcaming the defect of Li’s method. The cause of under-recovery is thought to be the presence of some unknown interfering factors in the plant. Both the modefied method and method Ⅱ can be used to determine the content of free sodium sulfanilate added to cell sap (no enzyme) of different plants without any significant difference (P = 0.1) . These facts indicate that the modified method in combination with method Ⅱ can be used to determine bound sodium sulfanilate in plant.更多还原